NWS Forecaster Discussion

Area forecast discussion
National Weather Service Houston/Galveston Texas
1255 PM CDT Tuesday Mar 31 2015
Aviation...
generally VFR decks through the evening hours...weakening winds
/mixing has ceilings filling back in to MVFR shortly after midnight
through 0900z. Isolated areas of (l)ifr visibilities with IFR decks
between 09-13z...especially if S-southeast winds die down to below 3
kts. Precipitation (shra/isolated ts) moving in from the west-southwest
should affect more western-inland terminals during the afternoon
hours. Next (late) period's rain chances are moderate at best
with the approach and passage of a weak shortwave trough. 31
&&
Previous discussion... /issued 1056 am CDT Tuesday Mar 31 2015/
Update...
see morning update.
Discussion...
at 10 am...a weak cold front extended from okc to lbb to El Paso.
12z sounding data supports temperatures in the lower to middle 80s this
afternoon. Visible satellite show a few more breaks than yesterday
with S-SW oriented cloud streets. Will make a few tweaks to the
sky grids but temperature forecast looks OK. 43
&&
Previous discussion... /issued 332 am CDT Tuesday Mar 31 2015/
Discussion...
an upper level shortwave trough moving into the Baja California California early this
morning will move across Texas on Wednesday. The models are then
developing a more zonal upper level flow for the remainder of the
week...with another shortwave trough then moving overhead during
the beginning of next week. Between these two upper level
events...a cold front is forecast by the models to push through
the forecast area late Friday and off the coast early Saturday.
In the near term...some patchy ground fog will affect some of the
more rural areas this morning. Will keep an eye on the extent of
the fog for any later updates. For now it does not look to be
widespread enough to mention in the forecast. Any fog that does
develop should burn off by middle morning.
A low to middle level high pressure ridge over the Gulf best seen at
850 mb is forecast by the models to help keep some ridging in
place on Wednesday when the first upper level shortwave moves
through the state. This in turn has led to slightly less rain
chances on Wednesday. The model output now indicates that the best
chances for rain will be more Wednesday morning and afternoon over
the northwestern counties...and Wednesday afternoon and evening
over the southern and eastern areas.
There does seem to be some disconnect between the 500 mb pattern
and the cold frontal passage Friday night. However...the models
are in decent agreement even though the GFS and European model (ecmwf) were still
about six hours apart. For now will go with a frontal passage
during the evening and overnight period. Following the front...the
models were coming together in moving at least one shortwave
trough overhead on Sunday. The European model (ecmwf) then builds a ridge a bit
more northward from the southern Gulf than the GFS on Monday. For
now will keep the rain mention in for Monday...although confidence
in the Monday forecast is not as high as for Sunday. 40
Marine...
light to moderate south winds will persist for the remainder of
the week. The area could see slightly higher winds and seas late
tonight and tomorrow as a storm system moves eastward across the
area. Our next cold front is still on schedule to race off the
coast and through the coastal waters late Friday night through
early Saturday morning with moderate to strong northeast winds and
building seas in its wake. Caution flags in the bays and
advisories for the 00-60 nm waters will likely be needed behind
the front. The moderate to strong northeast winds behind the front
will weaken late Saturday and on into Sunday and become more east
and southeast...and this light/moderate onshore flow will be in
the forecast for the start of next week. 42
&&
Preliminary point temps/pops...
College Station (cll) 64 79 64 83 65 / 10 50 30 20 10
Houston (iah) 64 80 66 83 67 / 10 40 30 20 10
Galveston (gls) 67 75 68 76 68 / 10 20 20 10 10
&&
Hgx watches/warnings/advisories...
Texas...none.
GM...none.
&&
$$
Discussion...43
aviation/marine...31